1. Field of the Invention
The present invention relates to compositions comprising nonpolymeric adamantyl compounds useful as anti-reflective coatings and/or planarization layers in lithography processes, including microelectronics fabrication processes.
2. Description of Related Art
Integrated circuit manufacturers are consistently seeking to maximize wafer sizes and minimize device feature dimensions in order to improve yield, reduce unit cost, and increase on-chip computing power. Improvements in lithography techniques and smaller-wavelength photolithography radiation sources now allow features close to 20 nm to be created. Reducing and/or optimizing the substrate reflectivity during photoresist exposure is critical for maintaining dimension control of such small features. Therefore, light absorbing organic polymers known as antireflective coatings are applied beneath photoresist layers in order to reduce the reflectivity normally encountered from the semiconductor substrates during the photoresist exposure.
Prior art anti-reflective coating layers contain a polymeric resin with a light-absorbing chromophore either attached to, or blended with, the resin. Although high optical densities enable these polymers to provide effective reflectivity control, they also have numerous drawbacks. For example, these polymers have high molecular weights that cause problems during polymer blending. More particularly, the use of these polymers inhibits customization of the antireflective coating to the photoresist being employed in the particular photolithographic process. Customization is extremely important because it allows for straighter profiles and better adhesion of the photoresist to the anti-reflective coating, thus resulting in better performance. Lower molecular weight components also allow better flow properties, which increase the material's ability to fill topography on the device surface and create a more planar surface for the photoresist application. Thus, there remains a need in the art for improved anti-reflective or planarization coating compositions.